_Fig._ 18. A Plumb-stone. _Fig._ 19. The claw of an American Crab; which, being on the opposite side of the mass containing the body, could not come in view with it at the same time. _Fig._ 20. The body of the crab, with other parts, appearing thro’ the stony matter that invelopes it, which appears to be an induration of yellow clay. _Fig._ 21. seems a long American Phaseolus. Part of the petrified husk is upon it. _Fig._ 22. An American Echinite of the flat kind, much resembling that species which Rumphius calls _Echinus sulcatus primus_. _Fig._ 23. _Arista cujusdam Graminis._ This body has all the characteristics of an ear of corn, or some species of grass, of which there are many. This has been taken for a spine of an Echinus: but, as we are to consider its nearest resemblance to whatsoever body, we must conclude it as we have said. I never saw any spine in the least like it; but an ear of corn, ripe and dry, is as susceptible of being petrified, as a crustaceous animal, in every respect. Indeed the spiculæ of the ear, each arising from the grain, being very slender, are of course destroyed during the petrifaction; but the form of the ear is actually preserved, as much as the nature and circumstances of the thing will allow. _Fig. a._ A manifest species of Pediculus Marinus crumped up. _b._ A Seed-vessel, given me by Mr. Da Costa, found in a clay-pit in Staffordshire. _c._ Cocculus Indicus. LII. _Observations upon the Comet that appeared in the Months of_ September _and_ October _1757, made at the Royal Observatory by_ Ja. Bradley, _D.D. Astronomer Royal, F.R.S. and Member of the Royal Academy of Sciences at_ Paris. [Read Dec. 22, 1757.] I Deferred to give an account of my observations upon the Comet that hath lately appeared, till I could settle the places of the stars with which it had been compared; several of them not being inserted in the British catalogue, and those which are, requiring some small corrections, which I have since made from my own observations. When I first discovered this Comet, it appeared to the naked eye like a dull star of the 5th or 6th magnitude; but viewing it thro’ a seven-foot Telescope, I could perceive a small Nucleus (surrounded, as usual, with a nebulous atmosphere), and a short tail extended in a direction opposite to the sun. Some small stars then appearing in the field of the telescope with the Comet, I measured its distance from them with a Micrometer; and on September 12ᵈ at 16ʰ 2’ mean time, I found it to be 1° 13’ 5" distant from a small star, whose right ascension was afterwards found to be 89° 49’ 40" and declination 36° 11’ 30" north: and near the same time the Comet was observed to be 43’ 10" from another star, whose right ascension was 90° 20’ 0" and declination 35° 12’ 0" north. Hence I collected, that the Comet’s right ascension was 89° 29’ 10“ and its declination 35° 0’ 20" north.